Sorry, no account deletion is possible as you can read here (including hints to anonimise your account):
http://support.ourworld.com/ics/support/KBAnswer.asp?questionID=796
URLS:
http://www.ourworld.com
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.